786 resultados para in-depth interviewing
Resumo:
The general objective of the study is to examine in depth the organisation and management practices of newspaper industry in Kerala with particular reference to the marketing aspects, with a View to suggesting measures for improving the economics and the managerial efficiency of the industry. The detailed investigation into the management aspects of the industry is done with particular reference to the two most popular Malayalam dailies in Kerala, namely, the Malayala Manorama and the Mathrubhumi. The purposeful selection of these two papers for the study is amply justified as these two dailies together account for about 80 percent of the total circulation of the newspapers in Kerala. Technically speaking, both these papers are owned by organisations registered as public limited companies and are, to a large extent professionally managed. The Malayala Manorama, though a public limited company in principle, functions, however, more or less as a private company or a family concern. These two papers therefore provide a scope for studying the management of newspaper industry practically under two different organisational set up, namely private limited company and public limited company The study has been divided into eight chapters. Chapter-I spells out an introduction about the newspaper industry and its unique features.Chapter-II, deals with a review of literature, objective, scope, methodology and limitations of the study. Chapter-III deals with origin, growth and status of newspaper industry. Chapter—IV examines the cost, revenue and profitability of the Malayala Manorama and Mathrubhumi. Chapter-V deals with the Organisation and Management. Chapter-VI examines the Marketing Management of Newspapers. Chapter-VII deals with the Marketing Strategy and Performance of Malayala Manorama and Mathrubhumi: An Assessment. Chapter-VIII presents the main findings of the study.
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Poor project planning, implementation and control and the subsequent cost and time overruns are ubiquitous features that have been posing serious concern at all levels - state, national and international. It results in wastage of the nation's scarce resources and retards the socio-economic progress. Although several studies peripheral on project overruns have been made at the national level, no serious attempt has been made at the state level to identify the magnitude of overruns, their causes and impacts on industrial projects. The present study "Time and Cost Overruns of Industrial Projects in Kerala" is an earnest attempt to probe in depth the time and cost overruns and their impact on industrial projects. The study places emphasise on the identification of the real reasons behind the cost and time overruns. It also covers the present project management practices of industrial projects in Kerala.
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Studies on pulse propagation in single mode optical fibers have attracted interest from a wide area of science and technology as they have laid down the foundation for an in-depth understanding of the underlying physical principles, especially in the field of optical telecommunications. The foremost among them is discovery of the optical soliton which is considered to be one of the most significant events of the twentieth century owing to its fantastic ability to propagate undistorted over long distances and to remain unaflected after collision with each other. To exploit the important propertia of optical solitons, innovative mathematical models which take into account proper physical properties of the single mode optical fibers demand special attention. This thesis contains a theoretical analysis of the studies on soliton pulse propagation in single mode optical fibers.
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Unfortunately, in India it is a fact that most of the investors are not interested in mutual funds. Those who are investing, they are investing only very small amounts. But what is important to be noted here is that when compared to other financial instruments, investments in mutual funds are safer and also yields more returns on the investment portfolio. Moreover as an investment avenue mutual fund is available for those investors who are not willing to take any exposure directly in the security market. It also helps such investors to build their wealth over a period of time. At the retail level, investors are unique and are highly heterogeneous, and the mutual fund schemes' selection will also differ depends on their expectations. Hence, investors’ expectation is a very important factor in this regard that needs to be analysed by all the investment houses. Hence, the factors that drive the investment decisions of individual investors to meet their expectations by investing money in mutual funds need an in-depth analysis. These driving forces include the preference of investors on mutual fund compared to various available avenues of financial investments, risk attitude of investors, influence of characteristics of instruments of mutual funds on investors, the investment specific attitudes of investors, and influence of qualities of fund management on investors. The success of any mutual fund, a popular means of investment, depends on how effectively an Asset Management Company has been able to understand the level of influence of these factors on the decision of investors to invest in mutual funds. For a substantial growth in the mutual fund market, there must be a high level precision in the design and marketing of the products of mutual funds taking into account these driving forces by the Asset Management Companies. Therefore, there is a need to conduct a detailed study on investments in mutual funds in this direction. A review of available literature also revealed that no detailed study on mutual funds has so far been attempted in this direction; hence the present study on Driving Forces of Investment Decisions in Mutual Funds is undertaken.
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From the early stages of the twentieth century, polyaniline (PANI), a well-known and extensively studied conducting polymer has captured the attention of scientific community owing to its interesting electrical and optical properties. Starting from its structural properties, to the currently pursued optical, electrical and electrochemical properties, extensive investigations on pure PANI and its composites are still much relevant to explore its potentialities to the maximum extent. The synthesis of highly crystalline PANI films with ordered structure and high electrical conductivity has not been pursued in depth yet. Recently, nanostructured PANI and the nanocomposites of PANI have attracted a great deal of research attention owing to the possibilities of applications in optical switching devices, optoelectronics and energy storage devices. The work presented in the thesis is centered around the realization of highly conducting and structurally ordered PANI and its composites for applications mainly in the areas of nonlinear optics and electrochemical energy storage. Out of the vast variety of application fields of PANI, these two areas are specifically selected for the present studies, because of the following observations. The non-linear optical properties and the energy storing properties of PANI depend quite sensitively on the extent of conjugation of the polymer structure, the type and concentration of the dopants added and the type and size of the nano particles selected for making the nanocomposites. The first phase of the work is devoted to the synthesis of highly ordered and conducting films of PANI doped with various dopants and the structural, morphological and electrical characterization followed by the synthesis of metal nanoparticles incorporated PANI samples and the detailed optical characterization in the linear and nonlinear regimes. The second phase of the work comprises the investigations on the prospects of PANI in realizing polymer based rechargeable lithium ion cells with the inherent structural flexibility of polymer systems and environmental safety and stability. Secondary battery systems have become an inevitable part of daily life. They can be found in most of the portable electronic gadgets and recently they have started powering automobiles, although the power generated is low. The efficient storage of electrical energy generated from solar cells is achieved by using suitable secondary battery systems. The development of rechargeable battery systems having excellent charge storage capacity, cyclability, environmental friendliness and flexibility has yet to be realized in practice. Rechargeable Li-ion cells employing cathode active materials like LiCoO2, LiMn2O4, LiFePO4 have got remarkable charge storage capacity with least charge leakage when not in use. However, material toxicity, chance of cell explosion and lack of effective cell recycling mechanism pose significant risk factors which are to be addressed seriously. These cells also lack flexibility in their design due to the structural characteristics of the electrode materials. Global research is directed towards identifying new class of electrode materials with less risk factors and better structural stability and flexibility. Polymer based electrode materials with inherent flexibility, stability and eco-friendliness can be a suitable choice. One of the prime drawbacks of polymer based cathode materials is the low electronic conductivity. Hence the real task with this class of materials is to get better electronic conductivity with good electrical storage capability. Electronic conductivity can be enhanced by using proper dopants. In the designing of rechargeable Li-ion cells with polymer based cathode active materials, the key issue is to identify the optimum lithiation of the polymer cathode which can ensure the highest electronic conductivity and specific charge capacity possible The development of conducting polymer based rechargeable Li-ion cells with high specific capacity and excellent cycling characteristics is a highly competitive area among research and development groups, worldwide. Polymer based rechargeable batteries are specifically attractive due to the environmentally benign nature and the possible constructional flexibility they offer. Among polymers having electrical transport properties suitable for rechargeable battery applications, polyaniline is the most favoured one due to its tunable electrical conducting properties and the availability of cost effective precursor materials for its synthesis. The performance of a battery depends significantly on the characteristics of its integral parts, the cathode, anode and the electrolyte, which in turn depend on the materials used. Many research groups are involved in developing new electrode and electrolyte materials to enhance the overall performance efficiency of the battery. Currently explored electrolytes for Li ion battery applications are in liquid or gel form, which makes well-defined sealing essential. The use of solid electrolytes eliminates the need for containment of liquid electrolytes, which will certainly simplify the cell design and improve the safety and durability. The other advantages of polymer electrolytes include dimensional stability, safety and the ability to prevent lithium dendrite formation. One of the ultimate aims of the present work is to realize all solid state, flexible and environment friendly Li-ion cells with high specific capacity and excellent cycling stability. Part of the present work is hence focused on identifying good polymer based solid electrolytes essential for realizing all solid state polymer based Li ion cells.The present work is an attempt to study the versatile roles of polyaniline in two different fields of technological applications like nonlinear optics and energy storage. Conducting form of doped PANI films with good extent of crystallinity have been realized using a level surface assisted casting method in addition to the generally employed technique of spin coating. Metal nanoparticles embedded PANI offers a rich source for nonlinear optical studies and hence gold and silver nanoparticles have been used for making the nanocomposites in bulk and thin film forms. These PANI nanocomposites are found to exhibit quite dominant third order optical non-linearity. The highlight of these studies is the observation of the interesting phenomenon of the switching between saturable absorption (SA) and reverse saturable absorption (RSA) in the films of Ag/PANI and Au/PANI nanocomposites, which offers prospects of applications in optical switching. The investigations on the energy storage prospects of PANI were carried out on Li enriched PANI which was used as the cathode active material for assembling rechargeable Li-ion cells. For Li enrichment or Li doping of PANI, n-Butyllithium (n-BuLi) in hexanes was used. The Li doping as well as the Li-ion cell assembling were carried out in an argon filled glove box. Coin cells were assembled with Li doped PANI with different doping concentrations, as the cathode, LiPF6 as the electrolyte and Li metal as the anode. These coin cells are found to show reasonably good specific capacity around 22mAh/g and excellent cycling stability and coulombic efficiency around 99%. To improve the specific capacity, composites of Li doped PANI with inorganic cathode active materials like LiFePO4 and LiMn2O4 were synthesized and coin cells were assembled as mentioned earlier to assess the electrochemical capability. The cells assembled using the composite cathodes are found to show significant enhancement in specific capacity to around 40mAh/g. One of the other interesting observations is the complete blocking of the adverse effects of Jahn-Teller distortion, when the composite cathode, PANI-LiMn2O4 is used for assembling the Li-ion cells. This distortion is generally observed, near room temperature, when LiMn2O4 is used as the cathode, which significantly reduces the cycling stability of the cells.
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With this document, we provide a compilation of in-depth discussions on some of the most current security issues in distributed systems. The six contributions have been collected and presented at the 1st Kassel Student Workshop on Security in Distributed Systems (KaSWoSDS’08). We are pleased to present a collection of papers not only shedding light on the theoretical aspects of their topics, but also being accompanied with elaborate practical examples. In Chapter 1, Stephan Opfer discusses Viruses, one of the oldest threats to system security. For years there has been an arms race between virus producers and anti-virus software providers, with no end in sight. Stefan Triller demonstrates how malicious code can be injected in a target process using a buffer overflow in Chapter 2. Websites usually store their data and user information in data bases. Like buffer overflows, the possibilities of performing SQL injection attacks targeting such data bases are left open by unwary programmers. Stephan Scheuermann gives us a deeper insight into the mechanisms behind such attacks in Chapter 3. Cross-site scripting (XSS) is a method to insert malicious code into websites viewed by other users. Michael Blumenstein explains this issue in Chapter 4. Code can be injected in other websites via XSS attacks in order to spy out data of internet users, spoofing subsumes all methods that directly involve taking on a false identity. In Chapter 5, Till Amma shows us different ways how this can be done and how it is prevented. Last but not least, cryptographic methods are used to encode confidential data in a way that even if it got in the wrong hands, the culprits cannot decode it. Over the centuries, many different ciphers have been developed, applied, and finally broken. Ilhan Glogic sketches this history in Chapter 6.
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The basic idea behind improving local food security consists of two paths; first, accessibility (price, stock) and second, availability (quantity and biodiversity); both are perquisites to the provision of nutrients and a continuous food supply with locally available resources. The objectives of this thesis are to investigate if indigenous knowledge still plays an important role in traditional farming in the Minangkabau`s culture, thus supporting local food security. If the indigenous knowledge still plays a role in food culture in the Minangkabau`s culture which is linked to the matrilineal role and leads to a sound nutrition. Further, it should be tested if marantau influences traditional farming and food culture in Minangkabau`s, and if the local government plays a role in changing of traditional farming systems and food culture. Furthermore this thesis wants to prove if education and gender are playing a role in changing traditional farming system and food culture, and if the mass media affects traditional farming systems and food culture for the Minangkabau. The study was completed at four locations in West Sumatera; Nagari Ulakan (NU) (coastal area), Nagari Aia Batumbuak (NAB) (hilly area), Nagari Padang Laweh Malalo (NPLM) (lake area), Nagari Pandai Sikek (NPS) (hilly area). The rainfall ranged from 1400- 4800 mm annually with fertile soils. Data was collected by using PRA (Participatory Rural Appraisal) to investigate indigenous knowledge (IK) and its interactions, which is also combining with in depth-interview, life history, a survey using semi-structured-questionnaire, pictures, mapping, and expert interview. The data was collected from June - September 2009 and June 2010. The materials are; map of area, list of names, questionnaires, voices recorder, note book, and digital camera. The sampling method was snowball sampling which resulted in the qualitative and quantitative data taken. For qualitative data, ethnography and life history was used. For quantitative, a statistical survey with a semi-structured questionnaire was used. 50 respondents per each site participated voluntarily. Data was analyzed by performing MAXQDA 10, and F4 audio analysis software (created and developed by Philip-University Marburg). The data is clustered based on causality. The results show that; the role of IK on TFS (traditional farming system) shown on NPLM which has higher food crop biodiversity in comparison to the other three places even though it has relatively similar temperature and rainfall. This high food crop biodiversity is due to the awareness of local people who realized that they lived in unfavourable climate and topography; therefore they are more prepared for any changes that may occur. Carbohydrate intake is 100 % through rice even though they are growing different staple crops. Whereas most of the people said in the interviews that not eating rice is like not really eating for them. In addition to that, mothers still play an important role in kitchen activities. But when the agriculture income is low, mothers have to decide whether to change the meals or to feel insecure about their food supply. Marantau yields positive impact through the remittances it provides to invest on the farm. On the other hand, it results in fewer workers for agriculture, and therefore a negative impact on the transfer of IK. The investigation showed that the local government has a PTS (Padi Tanam Sabatang) programme which still does not guarantee that the farmers are getting sufficient revenue from their land. The low agricultural income leads to situation of potential food insecurity. It is evident that education is equal among men and women, but in some cases women tend to leave school earlier because of arranged marriages or the distances of school from their homes. Men predominantly work in agriculture and fishing, while women work in the kitchen. In NAB, even though women work on farmland they earn less then men. Weaving (NPS) and kitchen activity is recognized as women’s work, which also supports the household income. Mass media is not yielding any changes in TFS and food culture in these days. The traditional farming system has changed because of intensive agricultural extension which has introduced new methods of agriculture for the last three decades (since the 1980’s). There is no evidence that they want to change any of their food habits because of the mass media despite the lapau activity which allows them to get more food choices, instead preparing traditional meal at home. The recommendations of this thesis are: 1) The empowerment of farmers. It is regarding the self sufficient supply of manure, cooperative seed, and sustainable farm management. Farmers should know – where are they in their state of knowledge – so they can use their local wisdom and still collaborate with new sources of knowledge. Farmers should learn the prognosis of supply and demand next prior to harvest. There is a need for farm management guidelines; that can be adopted from both their local wisdom and modern knowledge. 2) Increase of non-agricultural income Increasing the non-agricultural income is strongly recommended. The remittances can be invested on non-agricultural jobs. 3) The empowerment of the mother. The mother plays an important role in farm to fork activities; the mother can be an initiator and promoter of cultivating spices in the backyard. Improvement of nutritional knowledge through information and informal public education can be done through arisan ibu-ibu and lapau activity. The challenges to apply these recommendations are: 1) The gap between institutions and organizations of local governments. There is more than one institution involved in food security policy. 2) Training and facilities for field extension agriculture (FEA) is needed because the rapid change of interaction between local government and farmer’s dependent on this agency.
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Since its beginning in 1999, the Bologna Process has influenced various aspects of higher education in its member countries, e.g., degree structures, mobility, lifelong learning, social dimension and quality assurance. The social dimension creates the focus of this research. The social dimension entered the Bologna Process agenda in 2001. Despite a decade of reforms, it somehow remained as a vague element and received low scholarly attention. This research addresses to this gap. Firstly, different meanings of the social dimension according to the major European policy actors are analysed. Unfolding the understandings of the actors revealed that the social dimension is mostly understood in terms reflecting the diversity of population on the student body accessing to, progressing in and completing higher education, with a special concern on the underrepresented groups. However, it is not possible to observe a similar commonality concerning the actual policy measures to achieve this goal. Divergence occurs with respect to the addressed underrepresented groups, i.e., all underrepresented groups or people without formal qualifications and mature learners, and the values and institutional interests traditionally promoted by these actors. Secondly, the dissertation discusses the reflection of this social dimension understanding at the national level by looking at cases of Finland, Germany and Turkey. The in-depth analyses show an awareness of the social dimension among most of the national Bologna Process actors and a common understanding of the social dimension goals. However, this understanding has not triggered action in any of the countries. The countries acted on areas which they defined problematic before the Bologna Process. Finally, based on these findings the dissertation discusses the social dimension as a policy item that managed to get into the Bologna Process agenda, but neither grew into an implementable policy, nor drop out of it. To this aim, it makes use of the multiple streams framework and explains the low agenda status social dimension with: i. the lack of a pressing problem definition: the lack of clearly defined indicators and a comprehensive monitoring system, ii. the lack of a viable solution alternative: the proposal of developing national strategies and action plans closed the way to develop generic guidelines for the social dimension to be translated into national policy processes, iii. low political perceptivity: the recent trends opt for increasing efficiency, excellence and exclusiveness discourses rather than ensuring equality and inclusiveness iv. high constraints: the social dimension by definition requires more public funding which is less appreciated and strategic constraints of the actors in allocating their resources v. the type of policy entrepreneur: the social dimension is promoted by an international stakeholder, the European Students’ Union, instead of the ministers responsible for higher education The social dimension remains a policy item in the Bologna Process which is noble enough to agree but not urgent enough to act on.
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This study was aim to describe the indigenous knowledge of farmers at Nagari Padang laweh Malalo (NPLM) and their adaptability to climate change. Not only the water scarcity is feared, but climate change is also affecting their food security. Local food security can be achieved if biodiversity in their surrounding area is suitable to the local needs. The study was conducted by using Participatory Rural Appraisal (PRA) such as observation and discussion. The combination of in depth interview, life history, semi structure questionnaire, pictures, mapping and expert interviews was implemented. Data was analyzed by using MAXQDA 10 and F4 audio analysis software. The result shows awareness of the people and scarcity of water conditions has allowed the people of NPLM to face this challenge with wisdom. Aia adat (water resources controlled and regulate by custom) is one of their strategies to distribute the water. The general rule is that irrigation will flow from 6 pm – 6 am regularly to all farm land under supervision of kapalo banda. When rains occur, water resources can be used during the day without special supervision. They were used traditional knowledge to manage water resources for their land and daily usage. This study may be helpful for researcher and other farmers in different region to learn encounter water scarcity.
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In the pastoral production systems, mobility remains the main technique used to meet livestock’s fodder requirements. Currently, with growing challenges on the pastoral production systems, there is urgent need for an in-depth understanding of how pastoralists continue to manage their grazing resources and how they determine their mobility strategies. This study examined the Borana pastoralists’ regulation of access to grazing resources, mobility practices and cattle reproductive performances in three pastoral zones of Borana region of southern Ethiopia. The central objective of the study was to contribute to the understanding of pastoral land use strategies at a scale relevant to their management. The study applied a multi-scalar methodological approach that allowed zooming in from communal to individual herd level. Through participatory mapping that applied Google Earth image print out as visual aid, the study revealed that the Borana pastoralists conceptualized their grazing areas as distinctive grazing units with names, borders, and specific characteristics. This knowledge enables the herders to communicate the condition of grazing resources among themselves in a precise way which is important in management of livestock mobility. Analysis of grazing area use from the participatory maps showed that the Borana pastoralists apportion their grazing areas into categories that are accessed at different times of the year (temporal use areas). This re-organization is an attempt by the community to cope with the prevailing constraints which results in fodder shortages especially during the dry periods. The re-organization represents a shift in resource use system, as the previous mobility practice across the ecologically varied zones of the rangelands became severely restricted. Grazing itineraries of 91 cattle herds for over 16 months obtained using the seasonal calendar interviews indicated that in the areas with the severest mobility constraints, the herders spent most of their time in the year round use areas that are within close proximity to the settlements. A significant change in mobility strategy was the disallowing of foora practice by the communities in Dirre and Malbe zones in order to reduce competition. With the reduction in mobility practices, there is a general decline in cattle reproductive parameters with the areas experiencing the severest constraints showing the least favourable reproductive performances. The study concludes that the multi-scalar methodology was well suited to zoom into pastoral grazing management practices from communal to individual herd levels. Also the loss of mobility in the Borana pastoral system affects fulfilment of livestock feed requirements thus resulting in reduced reproductive performances and herd growth potentials. While reversal of the conditions of the situations in the Borana rangelands is practically unfeasible, the findings from this research underscore the need to protect the remaining pastoral lands since the pastoral production system remains the most important livelihood option for the majority of the Borana people. In this regards the study emphasises the need to adopt and domesticate regional and international policy frameworks such as that proposed by the African Union in 2010.
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Veränderungen des Raum-Zeit-Verhaltens im Zuge von Lebensumbrüchen und ihre Anforderungen an die Stadt- und Verkehrsplanung am Beispiel des Eintritts in den Ruhestand. In der vorliegenden Dissertation wurde untersucht, ob und in welchem Maße sich das Raum-Zeit-Verhalten im Alltag mit dem Eintritt in den Ruhestand verändert. Bei der Untersuchung handelt es sich um eine mehrjährige Panel-Studie, die in den Regionen Hamburg und Kassel durchgeführt wurde. Mit insgesamt 50 Studienteilnehmern wurden vor und nach ihrem Ausscheiden aus dem Erwerbsleben umfassende Interviews geführt. Hierbei kam die an der Oxford University entwickelte „HATS“-Methode („Household Activity Travel Simulator“) zum Einsatz, die einen tiefen Einblick in die Alltagsstrukturen und das aus ihnen resultierende raum-zeitliche Verhalten ermöglicht. Ein Untersuchungsschwerpunkt lag auf der Verkehrsmittelwahl. Auf Grundlage der Untersuchungsergebnisse wurden Handlungsempfehlungen für die Stadt- und Verkehrsplanung abgeleitet. Es zeigte sich, dass die Studienteilnehmer mit ihrem Eintritt in den Ruhestand grundsätzlich deutlich später im Tagesverlauf als Verkehrsteilnehmer in Erscheinung treten. Darüber hinaus zeichnete sich ein Bedeutungszuwachs des Stadtquartiers bzw. der nahräumlichen Mobilität ab; der Fuß- und Fahrradverkehr gewinnt für die Alltagsmobilität an Bedeutung. Versorgungs- und Dienstleistungsangebote im eigenen Wohnquartier – und somit nutzungsgemischte Stadtquartiere – erweisen sich demnach insbesondere für die Gruppe der Ruheständler als besonders relevant. Trotz der steigenden Bedeutung des Fuß-und Fahrradverkehrs zeigt die Studie, dass dem Pkw in der Alltagsmobilität eine (nach wie vor) dominante Rolle zukommt – eine Entwicklung, die sich aufgrund des Kohorteneffekts eher noch verstärken wird. Im Rahmen der Diskussion geeigneter Handlungsansätze für die Stadt- und Verkehrsplanung zur Stärkung des Umweltverbundes werden – neben Interventionen zur Attraktivitätsminderung des Pkw – insbesondere verschiedene Maßnahmen zu Angebotsverbesserungen im ÖPNV behandelt. Dabei wird u. a. auch die Verhaltensrelevanz von Kostenwahrnehmungen betrachtet. Zusätzlich wird deutlich, dass bei der Etablierung verkehrsplanerischer Maßnahmen auch die zu-nehmende Bedeutung von Wegen, die in Begleitung anderer Haushaltsmitglieder zurückgelegt werden (Stichwort: Haushaltsmobilität), berücksichtigt werden muss. Der Eintritt in den Ruhestand erweist sich grundsätzlich als eine Umbruchsituation im Lebensverlauf, die ein Aufbrechen von (Verkehrs-)Gewohnheiten im Alltag begünstigt und die Betroffenen besonders empfänglich für Informationen zu verschiedenen Verkehrsangeboten bzw. Verhaltens-alternativen werden lässt. Hinsichtlich möglicher Handlungsansätze wird in dieser Studie u. a. thematisiert, wie im Rahmen einer zielgruppenspezifischen Kommunikation im ÖPNV dieses Zeit-fenster genutzt werden kann, um Menschen an der Schwelle zum Eintritt in den Ruhestand als regelmäßige Nutzer von Bus und Bahn (neu) zu gewinnen bzw. zu halten.
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We discuss a variety of object recognition experiments in which human subjects were presented with realistically rendered images of computer-generated three-dimensional objects, with tight control over stimulus shape, surface properties, illumination, and viewpoint, as well as subjects' prior exposure to the stimulus objects. In all experiments recognition performance was: (1) consistently viewpoint dependent; (2) only partially aided by binocular stereo and other depth information, (3) specific to viewpoints that were familiar; (4) systematically disrupted by rotation in depth more than by deforming the two-dimensional images of the stimuli. These results are consistent with recently advanced computational theories of recognition based on view interpolation.
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Human object recognition is generally considered to tolerate changes of the stimulus position in the visual field. A number of recent studies, however, have cast doubt on the completeness of translation invariance. In a new series of experiments we tried to investigate whether positional specificity of short-term memory is a general property of visual perception. We tested same/different discrimination of computer graphics models that were displayed at the same or at different locations of the visual field, and found complete translation invariance, regardless of the similarity of the animals and irrespective of direction and size of the displacement (Exp. 1 and 2). Decisions were strongly biased towards same decisions if stimuli appeared at a constant location, while after translation subjects displayed a tendency towards different decisions. Even if the spatial order of animal limbs was randomized ("scrambled animals"), no deteriorating effect of shifts in the field of view could be detected (Exp. 3). However, if the influence of single features was reduced (Exp. 4 and 5) small but significant effects of translation could be obtained. Under conditions that do not reveal an influence of translation, rotation in depth strongly interferes with recognition (Exp. 6). Changes of stimulus size did not reduce performance (Exp. 7). Tolerance to these object transformations seems to rely on different brain mechanisms, with translation and scale invariance being achieved in principle, while rotation invariance is not.
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In macaque inferotemporal cortex (IT), neurons have been found to respond selectively to complex shapes while showing broad tuning ("invariance") with respect to stimulus transformations such as translation and scale changes and a limited tuning to rotation in depth. Training monkeys with novel, paperclip-like objects, Logothetis et al. could investigate whether these invariance properties are due to experience with exhaustively many transformed instances of an object or if there are mechanisms that allow the cells to show response invariance also to previously unseen instances of that object. They found object-selective cells in anterior IT which exhibited limited invariance to various transformations after training with single object views. While previous models accounted for the tuning of the cells for rotations in depth and for their selectivity to a specific object relative to a population of distractor objects, the model described here attempts to explain in a biologically plausible way the additional properties of translation and size invariance. Using the same stimuli as in the experiment, we find that model IT neurons exhibit invariance properties which closely parallel those of real neurons. Simulations show that the model is capable of unsupervised learning of view-tuned neurons. The model also allows to make experimentally testable predictions regarding novel stimulus transformations and combinations of stimuli.
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Reproduction is not restricted to the biological; it is also a complex and dynamic social process. The objective of this paper is to analyze the decision and planning of children as part of the reproductive process in men. Methodologically, a qualitative research was made. The analysis includes in-depth interviews with 30 parents between 20 and 45 years, of medium socio-economic level in México. The results show that the reproductive process incorporates family formation negotiated with their couple the marriage until they had economic potential. In some cases, their decision hastened because the couple was pregnant. The planning was not contemplated but when getting the news, they accept it and get involved in the process, while others see it as a conflict.